The Long Summer

Ultimately, the cause of global warming is only a side debate.

We live within the capsule of a global economy seemingly oblivious to climatic events with the potential to kill thousands — in a time when human populations have exploded and cities are the dominant form of human settlement.

With the Industrial Revolution, we took a giant stride into an era in which we are frighteningly exposed to potential cataclysm, enhanced by our own seeming ability to warm the earth and increase the probability of extreme climatic events.

The potential scale of disaster is almost unrecognizable in historical terms. At least 20 million people died of hunger and famine-related epidemics resulting from El Niño/Southern Oscillations (ENSOs) and droughts during the 19th century.

Today, over 200 million people live on agriculturally marginal lands in northeastern Brazil, the Saharan Sahel, Ethiopia and many parts of Asia.

Deforestation — to the tune of about the acreage of Arizona annually — strips the earth bare. Millions of us dwell in high-rise buildings, in suburban housing and slums in heavily industrialized cities that are extremely vulnerable to the violent storm surges of hurricanes.

Unlike the Cro-Magnons, the Chumash or even the Maya, we do not have the option to move elsewhere. Today, the neighboring lands are filled with our neighbors.

What would happen, for example, if the Greenland ice sheet were to release so much meltwater into the North Atlantic that the Gulf Stream abruptly shut down — just as it did in the Younger Dryas?

Would Europe be plunged into near-arctic conditions within a generation or less? Where would the present inhabitants of Scandinavia, Germany, France, the Netherlands, Poland, the Baltic states and Russia go — and what would they eat? There are scientists who believe such a climactic switch is entirely possible.

Optimism assumes that we will adapt to this new, more vulnerable world. We humans do indeed have a striking ability to adapt to changing environmental circumstances.

Yet, optimism fades in the face of demographic reality. Of the six billion of us who now inhabit the earth, hundreds of millions still subsist from harvest to harvest, from rainy season to rainy season — just as Stone Age and Bronze Age farmers did in Europe 5,000 years ago.

Famine is a remote danger in Europe and North America, with their industrial-scale agriculture and elaborate infrastructures for moving food over long distances.

Subsistence farmers and city dwellers on other continents, however, still live under the constant threat of hunger.

Every year, the media carry stories of famine and flood, of thousands perishing quietly in northeast Africa or Bangladesh, while the world remains oblivious. The numbers are hard for us to assimilate in the prosperous, seemingly invulnerable West.

They will become harder still to comprehend if global temperatures rise far above present levels, rising seas inundate densely populated coastal plains and force millions of people to resettle inland — or far more severe droughts settle over the Sahel and less well-watered parts of the world.

We can only imagine the death toll in a future era when climatic swings may be faster, more extreme — and completely unpredictable because of human interference with the atmosphere.

The millions who died in the Irish potato famine of the 1840s or the tens of millions who died from the Indian monsoon failures of the late 19th century will pale to insignificance.

Climate has helped shape civilization — but not by being benign. The unpredictable whims of the Holocene stressed human societies and forced them to either adapt or perish.

The collapses often came as a complete surprise to rulers and elites who believed in royal infallibility and espoused rigid ideologies of power.

There is no reason to assume that we have somehow escaped this shaping process.

Agriculture is less visible to us now — the number of people growing food has shrunk from 90% of the labor force in Europe 500 years ago to less then 3% in the United States today — but we still need to eat.

And now our vulnerability extends far beyond just growing food. Our crowded coastlines with densely packed high-rises and apartment buildings, our communication and transport systems, our abstract worlds of finance and scholarship and entertainment, are beholden to the world's climate in ways both obvious and hidden.

Like many civilizations before us, we have simply traded up in scale, accepting vulnerability to the big, rare disaster in exchange for a better ability to handle the smaller, more common stresses — such as short-term droughts and exceptionally rainy years.

But if we have become a supertanker among human societies, it is an oddly inattentive one.

Only a tiny fraction of the people on board are engaged with tending the engines.

The rest are buying and selling goods among themselves, entertaining each other or studying the sky or the hydrodynamics of the hull. Those on the bridge have no charts or weather forecasts — and cannot even agree that they are needed.

Indeed, the most powerful among them subscribe to a theory that says storms do not exist, or if they do, their effects are entirely benign — and the steepening swells and fleeing albatrosses can only be taken as a sign of divine favor.

Few of those in command believe the gathering clouds have any relation to their fate or are concerned that there are lifeboats for only one in ten passengers. And no one dares to whisper in the helmsman's ear that he might consider turning the wheel.

Adapted from The Long Summer by Brian Fagan, pp.250-252. All rights reserved. No part of this book may be used or reproduced without written permission from Basic Books, 387 Park Ave. South, New York, NY 10016.